Conventionally, as the gas turbine, there is one applied to, for example, a turbo shaft engine of a helicopter. Such a gas turbine includes a compressor, a combustor, and a turbine, where air taken from an air intake is compressed by the compressor to become high-temperature and high-pressure compressed air, the fuel is supplied to the compressed air by the combustor to cause combustion, so that the high-temperature and high-pressure combustion gas drives the turbine, and the rotative power is output to a transmission of the helicopter via a rotation shaft as an output shaft connected to the turbine. In this case, the turbine is constructed such that a plurality of stationary blades and moving blades is alternately arranged in a turbine cylinder, where the rotation shaft is rotated by driving the moving blades by the combustion gas. The combustion gas, which has driven the turbine, is converted to have a static pressure by a diffuser in an exhaust cylinder and then discharged to the air.
In this gas turbine, as a structure for supporting a bearing unit that rotatably supports the rotation shaft on the casing, the casing and the bearing unit are generally connected with each other by rigid connection via a support member.
For example, a frame structure of the gas turbine described in Patent Document 1 includes an outer periphery that connects radial inner ends of the support member with each other to form an inner wall of a combusted exhaust gas passageway, an inner corn portion for supporting a bearing, and front and rear inner walls for connecting the front and the rear of the outer periphery with the inner corn portion, respectively. The front and rear inner walls are constructed such that one of the front and rear inner walls has a low rigidity with respect to radial deformation, and the other has a sufficient rigidity (for example, see Patent Document 1).
Patent Document 1: Japanese Patent Application Laid-open No. H9-324699